Nigerian Boko Haram insurgents attacked a Cameroon military camp near the town of Waza in the north of the country on Monday, wounding several soldiers, an army spokesman said.

Chad, Niger and Cameroon have begun a joint offensive against Boko Haram militants who have killed thousands of people in a bid to carve out an Islamist emirate in northern Nigeria, and have increasingly staged raids across nearby borders.

"The wounded are being evacuated. The insurgents have been stopped. An APC (armoured personnel carrier) was taken from them and several of them were killed," a Cameroonian military officer told journalists in Maroua, adding the incident was continuing.